Obviously LP was set up by the cat. Cats are evil.
Notice how, in panel 2, the cat subtly catches the dog’s attention as he hears GG’s call for a confession.
Then in panel 3, the cat uses the fact that he has the dog’s eyes to look accusingly at LP. The dog cannot help but to be drawn in, making it look like they are both blaming LP.

Of course mustache cat hit LP over the head with the pot. That’s what makes it a perfect crime. The VICTIM is blamed.
We all know how unaware LP is of his surroundings. He even got lost in his own front yard. The nefarious cat took advantage of that.
Are we supposed to believe that LP managed to knock over a pot with his head? Flowers are normally kept at waist level or lower so they can be easily seen by all.
So how did a leaf get on LP’s head? An assault by the cat.